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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In somatic cell hybrids between the pseudodiploid Thy-1- Abelson-leukemia-virus-induced pre-B cell lymphoma RAW 253.1 and the Thy-1+ T-cell lymphoma, AKR1 (Thy-1+), all cells express the Thy-1 allele of the T-cell parent but most hybrid cells do not express the Thy-1 allele of the pre-B cell lymphoma parent. The Thy-1 allele of the pre-B cell parent, however, is spontaneously activated in a minor proportion of hybrid cells. By sorting for cells expressing the Thy-1 allele of the pre-B cell parent, derivative clones in which 100% of cells express both parental Thy-1 alleles can be isolated. Revertants with a phenotype identical with that of the original hybrid cell line can be isolated from these derivatives by sorting for nonexpression of the Thy-1 allele of the pre-B cell parent. These first-generation revertant cell lines have lost one copy of the Thy-1 gene derived from the pre-B cell lymphoma parent. By a further cycle of sorting, derivatives in which 100% of cells express both parental Thy-1 alleles can again be obtained. Second-generation revertants isolated by sorting these Thy-1+ hybrid cells for nonexpression of the Thy-1 allele of the pre-B cell parent no longer contain a normal copy of the pre-B cell Thy-1 allele and this surface antigen is no longer expressed by any cells in the population. These results are consistent with a mechanism that sequentially activates each copy of the Thy-1 gene derived from the pre-B cell lymphoma parent. Hybrids between the class D Thy-1- mutant, AKR1 (Thy-1- d), in which the 5' region of the Thy-1 structural gene has been deleted, and RAW 253.1 cannot be activated to express either Thy-1 allele. This result indicates that a sequence upstream of exon 2 of the active Thy-1 allele is critical for the initial activation event.
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PMID:Sequential activation and loss of the pre-B cell Thy-1 gene in T-cell X pre-B cell somatic hybrids. 289 32

A series of murine B lymphoid tumor cell lines which are representative of the pre-B cell, immature and mature B cell, and plasma cell stages of B cell development have been examined for expression of c-myb proto-oncogene mRNA. The pre-B cell lymphoma cell lines express equivalent high steady state levels of c-myb mRNA. In contrast, the B cell lymphoma and plasmacytoma cell lines express steady state c-myb mRNA at levels which are 0.005 to 0.1 times that of the pre-B cell lymphoma lines. These results correlate high levels of c-myb mRNA expression with the pre-B cell stage of development. Subclones of the 1881 pre-B cell lymphoma which express K light chain and are surface IgM-positive as well as two types of hybrid B lymphoid cell lines have been used to demonstrate that surface immunoglobulin expression is not sufficient to result in the down-regulation of c-myb mRNA levels or changes in the expression N-myc mRNA, lambda 5 mRNA, or the BP-1 surface antigen which are markers of the pre-B cell stage of development. Thus, changes in the expression of genes which are independent of immunoglobulin expression are associated with transition from the pre-B cell to the immature B cell stage of development.
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PMID:Differential expression of the c-myb proto-oncogene marks the pre-B cell/B cell junction in murine B lymphoid tumors. 331 89

The genes that code for the human major histocompatibility class I antigens, HLA-A2 and HLA-B7, were introduced into human, monkey, and mouse cell lines by cotransfection with suitable biochemical markers and the fluorescence-activated cell sorter was used to identify and/or select stable cell populations expressing high surface levels of these antigens. Levels of expression obtained were similar to those observed for endogenous HLA antigens on various human cell lines and were 25-80% of those observed on the human B-lymphoblastoid cell line JY. Serologically defined HLA-A2 and HLA-B7 polymorphic determinants remained intact on all transfected recipient cells analyzed. Cloned human allospecific cytotoxic T lymphocytes (CTL) specific for HLA-A2 or HLA-B7 were capable of lysing appropriate HLA-transfected human cells with comparable efficiency to JY cell lysis. Two of 10 CTL clones lysed appropriate monkey cell transfectants with approximately equal to 20% the efficiency of human cell transfectants. No specific lysis of any HLA-transfected mouse cell lines, including a B cell lymphoma, was observed despite comparable levels of surface antigen expression or after induction of higher levels by mouse gamma-interferon. Furthermore, L cells expressing human beta 2-microglobulin in addition to HLA-A2 or -B7 were not lysed by these CTL. Thus, an additional species-specific component may be involved in lysis by allogeneic CTL--possibly related to the function(s) of other surface proteins on target cells.
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PMID:Recognition of HLA-A2 and -B7 antigens by cloned cytotoxic T lymphocytes after gene transfer into human and monkey, but not mouse, cells. 639 Apr 42

We report the use of a bispecific F(ab')2 antibody to target the ribosome-inactivating protein saporin to the surface antigen CD22 in the treatment of low-grade, end-stage, B-cell lymphoma. Four patients were treated. Toxic effects were minimal (grade I), with mild fever, weakness, and myalgia for 1-2 days after treatment. One patient showed an antibody response to mouse Fab' and saporin. All patients showed rapid and beneficial responses to treatment with improvements in most disease sites and in peripheral blood cytopenia. The responses were short-lived (less than 28 days) but further study of this targeting system is warranted.
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PMID:Treatment of B-cell lymphomas with combination of bispecific antibodies and saporin. 754 57

LL2 is a murine monoclonal antibody (MAb) that has been shown to be effective for the diagnosis and treatment of patients with non-Hodgkin's B cell lymphoma. Studies have also shown that radiolabeled murine LL2 (mLL2) or mLL2 and fragments thereof coupled to Pseudomonas exotoxin (PE) can effectively target human B cell lymphoma in mice. We have obtained the DNA sequences encoding the VK and VH domains of mLL2, an IgG2a MAb, which were combined with their respective human kappa and IgG1 constant region domains and expressed in SP2/0 cells. Like its murine counterpart, the chimeric LL2 (cLL2) antibody is glycosylated in the light chain variable region. Chimerization did not interfere with the immunoreactivity of the antibody, as determined by a competitive binding assay, where either antibody shows equivalent inhibition of the binding of its counterpart to the Raji cell membrane surface antigen, CD22. Both antibodies bind and are rapidly internalized by Raji cells, whereas an irrelevant humanized antibody did not bind and was not internalized under similar conditions. The internalization rates of the bound murine or chimeric antibodies were nearly identical, with Ke values of 0.106 and 0.118 min-1 for mLL2 and cLL2, respectively. The observed close equivalence between the murine and chimeric antibodies suggests potential advantages of the latter as a less immunogenic agent. Studies are currently underway to evaluate the chimeric antibody as a potential therapeutic immunoconjugate.
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PMID:Chimerization of LL2, a rapidly internalizing antibody specific for B cell lymphoma. 773 71

Two monoclonal antibodies (FB1 and FB21) reactive in formalin-fixed, paraffin-embedded tissue sections are reported in this paper. FB1 and FB21 recognize a cytoplasmic antigen and a surface antigen of B cells, respectively. FB1 reacts with mantle zone (MZ) B cells, germinal centre (GC) cells, and marginal zone (MrZ) B cells, but not with T cells in lymphoid tissues. FB21 reacts with MZ B cells, GC cells in lymphoid tissues, and T cells of peripheral blood, but not with MrZ B cells in the spleen. Neither monoclonal antibody (MoAb) reacts with monocytes, granulocytes, or plasma cells. FB1 reacted with all the B-cell lymphomas tested and with CD20-positive Reed-Sternberg cells in two of five cases of Hodgkin's disease, but not with multiple myelomas or T-cell lymphomas. FB21 reacted with B-cell lymphoma in 20 of 22 cases, but not with multiple myelomas, T-cell lymphomas, or Reed-Sternberg cells of Hodgkin's disease. Immunoprecipitation studies revealed that FB1 recognizes the same two polypeptide chains that are recognized by L26 and is a member of the CD20 antibody cluster. FB21 was thought to recognize a sialic acid-dependent carbohydrate epitope and this was confirmed at the Fifth International Conference on Human Leukocyte Differentiation Antigens (Boston, 1993). FB21 did not react with splenic MrZ B cells and was different from the pan B markers reported previously [CD20 (L26), CD45RA (MB1), and CD74 (LN-2)]. FB21 recognizes a subset of B cells and appears to be closely related to CD75/76 antibodies. FB1 and FB21 are useful MoAbs for the diagnosis and analysis of B-cell lymphomas.
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PMID:Production of two monoclonal antibodies (FB1 and FB21) useful for the identification of human B lymphocytes in formalin-fixed, paraffin-embedded tissues. 796 94

This study examines the identification of unusual cell populations highly associated with lymphoma cells (UCP-L) in diagnostic biopsy specimens using three-color flow cytometry (3-FCM). Patterns of surface antigen expression were used to compare the morphology of distinct lymphoid cell populations present in biopsy specimens and determine the presence or absence of UCP-L. UCP-L were identified by their larger size as compared to admixed reactive lymphocytes, and the method is based on the concept that neoplastic lymphoma cells are larger than reactive lymphocytes. The comparison of relative cell sizes was determined by overlaying forward scatter histograms by multicolor gating using PAINT-A-GATE software. In order for separate gates to be set on UCP-L and reactive cell populations, UCP-L had to fulfill one or more immunophenotypic criteria. These included: (1) belonging to a subset of B cell antigen-positive cells showing restricted expression of kappa or lambda light chains; (2) belonging to a subset of CD4-positive cells having dim or absent expression of CD45RA; (3) showing alterations in antigen expression (loss, dimmer or brighter); or (4) expressing an immunophenotype that is present on only rare cell populations or is absent from reactive lymph nodes. The immunophenotypic profiles of the respective cell populations were demonstrated by cubic representations to assess more easily the co-expression of three antigens. The common morphology of UCP-L as defined by forward and side scatter grams was consistent with a 'lymphoid appearance' except in several cases of HTLV-I-positive T cell lymphoma and gammadelta T cell lymphoma. The immunophenotypic profiles of UCP-L were confirmed to correspond to the presumptive lymphoma cell population by use of a live gating procedure on the large cells, which eliminated interference by reactive cells or necrotic tissue fragments. Using this method, we identified UCP-L in 208 of 293 (71%) consecutive cases of non-Hodgkin's lymphomas, while no UCP-L were seen in 72 cases of non-specific hyperplasia of lymph nodes. Twenty-seven cases could not properly be examined about the existence of UCP-L because of massive necrosis, extensive fibrosis or strong non-specific staining reactions of unknown cause. When those cases were eliminated from the analysis, 80% of non-Hodgkin's lymphoma were found to contain UCP-L. In B cell lymphoma, the incidence of UCP-L in nodal lymphomas (80%) was much higher than in extranodal lymphomas (47%). Only one of 21 cases of Hodgkin's lymphoma was found to have UCP-L. The 3-FCM procedure was validated by the combined use of immunohistochemistry, morphologic examination, cytogenetic and antigen receptor gene rearrangement analysis by Southern blot hybridization. Our findings indicate that detection of UCP-L by 3-FCM is a reliable method to distinguish non-Hodgkin lymphomas from reactive hyperplasias in the majority of cases, even when the reactive cell population predominates over the malignant cell population.
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PMID:Three-color flow cytometry in the diagnosis of malignant lymphoma based on the comparative cell morphology of lymphoma cells and reactive lymphocytes. 936 23

High-grade mucosa-associated lymphoid tissue (MALT) B-cell lymphoma of the stomach shares several features with its low-grade counterpart. The latter is nearly invariably associated with Helicobacter pylori, and the tumor cells of all MALT lymphomas normally express surface antigen receptors; thus, it is possible that the high-grade type, like the low-grade type, is still influenced by interaction with antigen. In the present study, we analyzed the immunoglobulin heavy chain variable (V)-region genes from eight cases of high-grade MALT lymphoma and one case of Burkitt's lymphoma of the stomach. The V-region genes revealed somatic mutations in all cases, leading to the conclusion that high-grade MALT lymphomas derive from antigen-experienced (post-) germinal center B-cells. Nonrandom distribution of replacement and silent mutations within the gene segments in seven of the eight MALT lymphomas indicated that these V-region genes were selected by antigen, at least for some period of time. Five of the cases showed an unusual mutation pattern that was suggestive of selection by autoantigen or superantigen rather than heterogeneous antigen. Analysis for intraclonal variations revealed evidence of ongoing mutations in two cases. In these cases, the tumor clones probably derived from cells affected by a germinal center B-cell reaction, as the microenvironment of the germinal center is required for maintenance of an active hypermutation mechanism. On the other hand, in another two cases, no evidence of intraclonal variations was found. Thus, either these tumor clones were derived from postgerminal center B-cells, or the hypermutation mechanism in the germinal center ceased after some period of time. Given the mutation pattern, it is possible that high-grade MALT lymphomas emerge from further transformation of low-grade MALT lymphomas with accumulation of additional mutations in the complementarity-determining regions.
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PMID:Immunoglobulin VH genes of high-grade mucosa-associated lymphoid tissue lymphomas show a high load of somatic mutations and evidence of antigen-dependent affinity maturation. 952 Sep 41

CD5 surface antigen is expressed on some categories of B cell lymphomas. The detection of CD5 coexpression on malignant B cell infiltrates, particularly in small biopsy specimens, is useful in distinguishing between small lymphocytic lymphoma, mantle cell lymphoma, low grade marginal zone B cell lymphoma, and follicular small cleaved cell lymphoma. However, conflicting results have been reported with regard to the detection of CD5 antigen expression on B cell non-Hodgkin's lymphomas (B-NHLs) in fixed, paraffin embedded tissues using routine immunohistochemical (IHC) staining techniques. We used catalyzed reporter deposition (CARD) as a strategy to amplify the IHC signal and consequently increase the sensitivity of antigen detection. CARD improved detection of CD5 antigen without sacrificing specificity of the test. In our study, virtually all malignant B-NHLs with CD5 antigen expression showed strong immunoreactivity for a commercially available anti-CD5 monoclonal antibody using CARD, whereas the majority of the same lymphomas did not label for CD5 using routine IHC without CARD amplification. The concordance between CD5 antigen detection by immunophenotyping of fresh or frozen tissues and immunostaining with CARD amplification on paraffin fixed tissue sections was 100%. It appears that this method can be applied in the diagnostic evaluation of B-NHLs or in other situations that a weak antigen signal is present.
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PMID:Detection of CD5 antigen on B cell lymphomas in fixed, paraffin embedded tissues using signal amplification by catalyzed reporter deposition. 961 89

Primary cutaneous lymphomas present in and are confined to the skin with no evidence of extracutaneous disease. The skin is the second most common extranodal site involved by primary lymphoma; 50% are mycosis fungoides (MF)-type cutaneous T-cell lymphoma, with the remainder being peripheral T-cell lymphoma (25%) and B-cell lymphoma (25%). The diagnosis of non-MF primary cutaneous lymphomas differs from that of nodal lymphomas: (1) presentation in the skin more often predicts outcome than histology, (2) immunophenotyping and immunogenotyping studies show differences in chromosomal translocations, cell-surface antigen expression (T-cell receptor [TCR] and immunoglobulin [Ig] heavy and light chains), and oncogene expression, (3) involvement of structural compartments of the skin (epidermis, periadnexal or adventitial dermis, interstitial dermis, and subcutis) aids differential diagnosis in place of nodal architecture, and (4) cytokine and extracellular matrix environments may influence behavior of cutaneous lymphomas. Diagnosis often requires coordinated evaluation of clinical history, immunohistochemistry on paraffin and frozen sections of skin biopsies, and molecular analysis. Classification of primary cutaneous lymphomas by a combined histologic type and clinical behavior is useful.
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PMID:Primary cutaneous lymphomas other than mycosis fungoides. 1037 86


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